Editor's Note: The following comes to us from University of Georgia political science professor, Paul Gurian.
In her 2000 article "The End Game in Post-Reform Presidential Nominations", Barbara Norrander evaluated several indicators of when a nomination campaign is effectively over, specifically, when the frontrunner's last remaining opponent would drop out of the race. Two of these indicators are especially relevant at this point in time: the "gain-deficit ratio" (Collat, Kelley and Rogowski, 1981) and the "bandwagon curve" (Straffin, 1977).
These formulas are not precise predictors of when a candidate will drop out -- that is a decision made by the candidate and her staff. However they do indicate when conditions are such that the frontrunner's nomination seems inevitable -- conditions that figure into the opponent's decision-making.
Before the Indiana and North Carolina primaries, Obama needed 273 delegates to achieve a majority. To exceed the gain-deficit ratio threshold of .36, he needed to win 98.3 delegates. On Tuesday he won approximately 97 or 98 pledged delegates (estimates vary from 95-100). However, he also won about 10 super-delegates the next day. Whether the super-delegates are counted as part of the same "event" or not, Obama is very close to, or just above the threshold. (These numbers change if one assumes that the Michigan and Florida delegates will be seated.)
The Straffin formula suggests that Obama is still just shy of the "bandwagon" threshold. Considering the delegates won by each candidate, the current delegate margin (Obama's delegate total divided by Clinton's) is 1.09, not quite enough to exceed the current threshold of 1.14 (see below).
Although it is still possible for Clinton to win the nomination, there is an emerging consensus among reporters and politicians that the race is over. This perception coincides with the two mathematical indicators: it's not over yet, but it's very close.
BO 1854; HRC 1696 (as of 5/9)
total BO+HRC = 3550
total all dels = 4049
BO+HRC/totalDels = 0.876759693752
4.596 - 7.28 + 3.824 = 1.14
BO/HRC = 1.09
--posted by Paul-Henri Gurian (Associate Professor of Political Science, University of Georgia)
Related: (from fivethirtyeight.com...)
ABC News: Obama Now Leads in Superdelegates
Obama's Slide Revisited
Unpledged Add-On Delegates